How to create a Twitter List from someone's Twitter Following list?

Let's say you want to create a list from the list of people someone else is following.
Imagine you want to have a "What would Oprah see?" list. As long as they are following less than 500 accounts (which is Listpedia current limit), it's a very trivial task.

Click "Make a List", select "Twitter List", give it a name (description and tags are optional).

Go to Twitter and navigate to the Following list of the account you are interested in, as in
https://twitter.com/Oprah/following